A hand-held terminal for receiving, storing and transmitting information is disclosed. The terminal has a keyboard, a display and is powered by internal, rechargeable batteries. An internal battery charging circuit includes a fixed voltage power supply which is controlled to provide a constant current charging current. A low-power radio frequency transceiver, for example, of a spread spectrum technology (SST) device is provided for receiving and transmitting information between the terminal and a base radio transceiver. A modular, magnetic credit card reader is operably and removably attached to the terminal and is interchangeable with a scanner of the type which can read bar codes or the like. Modules display screens, processor/memory modules, modular keyboards, and operating handles are also shown. A modular, compact printer can also be attached to the hand held terminal. Interactive pen based display screens can be used to allow information to be input directly on the screen.